Unit 2. Signaling and Single Area OSPF

Transcription

1 nit ignaling and ingle rea PF

2 elecommunications ignaling

3 ignaling g sed to provide all of the set up, tare down and call processing information such as: ff hook notification alling party number alled party number ircuit D n hook notificcation

4 ignaling g ethods n-band signaling sent on same circuit as information. Robbed bit signaling g is the most common method of in band signaling used ut of band signaling uses a separate path between switches also called ommon hannel ignaling () 7 ignaling ystem 7 is the system used in orth merica ingle and ultifrequency signals refer to tones used to establish connections between switches ar outh the D voltage used in P

5 Robbed Bit ignaling g Robbed bit signaling uses the least significant bit to carry signaling information

6 Robbed Bit ignaling g nit

7 ommon hannel ignaling g ommon channel signaling g is when a separate network is used for signaling such as 7

8 D ut of band signaling used between the customer and the central office Basic rate has B+d ( data channels and one signaling channel) Primary rate has 3B+d (3 data channels and 1 signaling channel)

9 dvanced ntelligent etwork () Provides the ability to make database inquiries anywhere in the network Primary uses are: 800 number translation 800 number portability ocal number portability aller D

10 ingle rea PF

11 ink tate Routing ink tate automatically builds the network topology and then selects the best path. Reports outages to neighbors and recalculates the path (PF, -) end state changes to its neighbors who forward to its neighbors, etc. in a link state announcement () Divides network into areas and maintains a topology database. Backbone (border) area is area 0 ses costs to determine best path Faster convergence than distance vector routing ses the Hello protocol to discover its neighbors

12 ype of ink tate etworks Broadcast networks Hello intervals default is 10 seconds Dead intervals four times the hello interval so default is 40 seconds on Broadcast networks Hello intervals default is 30 seconds Dead intervals four times the hello interval so default is 10 seconds

13 Benefits se cost metrics to determine the best route sually only send updates when a change occurs leading to faster convergence an segment network for more efficiency end updates as soon as a change occurs so routing loops are very unlikely l roubleshooting is usually easier f you understand d the link state t concepts cale to larger networks better than distance vector protocols

14 imitations Require the following: Routing table Forwarding table table of network prefixes and next hops djacency database lists all neighboring routers and their relationships sing Dijkstra s s algorithm require more processing power and memory so the routers are more expensive When first brought up the discovery process can flood the network with and degrade performance

15 pen hortest Path First (PF) reas - Breaks network into areas which are autonomous systems utonomous ystems () collections of networks that have a common administration and share a common routing strategy. lso called a routing domain. Require a backbone area which h serves as a gateway between the areas rea Border Router (BR) router in the area that communicate with the backbone area Boundary Router connects to another routing domain Designated router assigned by administrator

16 ink tate

17 xternal Routes ne Router only advertise default route ore than one router can either pick the closest or the most efficient one etrics can use either the internal metrics or assign ones for external communications xternal routes added to database as gateway link state records

18 hortest Path First lgorithm Places each router as the root of the tree dds that router to each router closest to it fter doing this for all the router in the network will have the shortest path to anywhere

19 ink tate Database ach area has its own database ach database consists of the following: Router link advertisements etwork link advertisements ummary link advertisements external advertisements

20 oad Balancing an use cost to load balance by giving selected links identical costs hat way the router will select whichever one has the shortest queue to send data

21 ingle rea PF ses a area hierarchical design solate intra-area s to that area dvantages: ed to recalculate the PF (shortest path first) less frequently Has smaller routing tables ess overhead to maintain the link state updates

22 ost ost is determined by the bandwidth of each link ost = 100,000,000, / bandwidth in bits per second xample 100,000,000 / 10bps = 10 8 / 10 7 = / 1,544,000 = 64 peed ost 1 64 FDD 1 10 B th 10 1 GB th 1 1 You can manually change the cost if you want to Router(config-if)#ip ospf cost (number)

23 etup Router(config)#router ospf is the process D which can arbitrarily be assigned locally Router(config)#network (wildcard- mask)area (area-id) ets the access permissions for the area You can use router authentication

24 ther seful PF ommands show ip protocol show ip route show ip ospf interface show ip ospf neighbor debug ip ospf events debug ip ospf packet